Abstract：Objective Pulsatile tinnitus (PT) is a pulse-synchronous tinnitus. Many PT cases have objective sound source in the patient’s head. Sigmoid sinus (SS) is widely suggested to be a primary sound source of PT, and the SS venous sound might transmit into tympanic cavity through temporal bone air cells (TBAC). The hypothesis suggested that the hyperpneumatization of TBAC might amplify the venous sound and induce PT, but presently without quantitative research in view of biomechanics. Method Through the in vitro experiment, the generation and transmission pathways of the venous sound were simulated. The sound signals at the position of eardrum were recorded and analyzed. Result In case of cortical plate dehiscence, the high pressure and pulse-synchronous venous sounds were received at eardrum. The highest sound pressure occurred in the normal pneumatization case. In case of cortical plate intactness, the non-pulsatile venous sounds with pressure close to the background control sound were received at eardrum. TBAC with different pneumatization grades would transmit venous sound in different frequency range. Conclusion Normal pneumatization TBAC exhibits the highest amplification on venous sound, while hypopneumatization TBAC exhibits the lowest amplification on venous sound. The pneumatization grade of TBAC is neither sufficient nor essential condition of pathogenic venous sound, while the cortical plate dehiscence is the sufficient condition of pathogenic venous sound.In case of cortical plate dehiscence, TBAC with all pneumatization grades would induce venous sound. In case of cortical plate intactness, TBAC with all pneumatization grades would not induce venous sound.